Transfer function and high dynamic range images
AssigneeApple Inc.
InventorGabriel G. Marcu
Life of this patent
Estimating the term…
Abstract
Methods and apparatuses to derive at least one exposure function for high dynamic range imaging from images of different exposure durations. In one aspect, a method to generate a high dynamic range image from a plurality of images taken with a plurality of exposure durations respectively, includes: computing an exposure function from the plurality of images; and combining the plurality of images into a high dynamic range (HDR) image using the exposure function. In one example of an embodiment, the exposure function is evaluated through: evaluating first data representing a derivative of the exposure function from pixel values of the plurality of images; and integrating the first data to generate second data representing the exposure function.
Claims34
A machine readable storage medium storing executable computer program instructions which when executed by a data processing system cause said system to perform a method for high dynamic range imaging, the method comprising:
- evaluating first data representing a derivative of an exposure function from pixel values of a plurality of images taken with a plurality of exposure durations respectively, wherein at least some of the pixel values represent a region receiving substantially constant irradiance in the plurality of images;
- and
- integrating the first data to generate second data representing the exposure function.
A method of image processing, the method comprising:
- evaluating first data representing a derivative of an exposure function from pixel values of a plurality of images of a scene taken with a plurality of exposure durations, wherein at least some of the pixel values represent a region receiving substantially constant irradiance in the plurality of images;
- integrating the first data to generate second data representing the exposure function;
- and
- generating an image, for display on a display device, of the scene from the plurality of images and the second data representing the exposure function.
A data processing system for image processing, the data processing system comprising:
- means for evaluating first data representing a derivative of an exposure function from pixel values of a plurality of images of a scene taken with a plurality of exposure durations, wherein at least some of the pixel values represent a region receiving substantially constant irradiance in the plurality of images;
- and
- means for integrating the first data to generate second data representing the exposure function.
An image capturing device, comprising:
- memory;
- an image sensing device coupled to the memory to generate a plurality of images of a scene with a plurality of exposure durations;
- and
- a processing circuit coupled to the image sensing device, the processing circuit to compute an exposure function from the plurality of images and combine the plurality of images into a high dynamic range (HDR) image using the exposure function,
- wherein to compute the exposure function the processing circuit is to:
- evaluate first data representing a derivative of the exposure function from pixel values of the plurality of images and the plurality of exposure durations, wherein at least some of the pixel values represent a region receiving substantially constant irradiance in the plurality of images;
- and
- integrate the first data to generate second data representing the exposure function.
A machine readable storage medium storing executable computer program instructions which when executed by a data processing system cause said system to perform a method for high dynamic range imaging, the method comprising:
- receiving a plurality of images taken with a plurality of exposure durations respectively;
- determining differences in exposure durations with respect to differences in pixel values of the plurality images to evaluate an exposure function;
- and
- determining an irradiance map from the plurality of images using the exposure function,
- wherein said determining differences in exposure durations with respect to differences in pixel values of the plurality images comprises:
- determining a ratio between a difference in logarithm of two exposure durations and a difference in pixel values in two of the plurality of images taken with the two exposure durations respectively.
A machine readable storage medium storing executable computer program instructions which when executed by a data processing system cause said system to perform a method for high dynamic range imaging, the method comprising:
- receiving a plurality of images taken with a plurality of exposure durations respectively;
- determining an exposure function from mathematically integrating a slope curve of the exposure function derived from the plurality of images and the plurality of exposure durations;
- and
- recovering a high dynamic range (HDR) image from the plurality of images and the plurality of exposure duration using the exposure function.
An image capturing device comprising:
- a memory;
- an image sensing device coupled to the memory to generate a plurality of images with a plurality of exposure durations;
- and
- a processing circuit coupled to the image sensing device, the processing circuit configured to
- determine an exposure function from a mathematical integration of a slope curve of the exposure function derived from the plurality of images and the plurality of exposure durations;
- and
- recover a high dynamic range (HDR) image from the plurality of images using the exposure function.
Dependencies are inferred from the claim text.